Walden University BIOL1001 WEEK 5 Exam.

Question 1 The phrase “survival of the fittest” is somewhat misleading because it implies that: Answer: C. The best possible organism will evolve Question 2 Choose the best answer. The logic of natural selection predicts that a population of organisms will undergo evolution if, and only if, which of the following condition(s) exist? Answer: D. Both b and c. Question 3 Your friend was diagnosed with strep throat 2 months ago. She was treated with antibiotics for 10 days, but 2 weeks after treatment, the symptoms returned. She was given a different antibiotic, and her symptoms again initially improved but then got worse. What is happening? Choose the best answer. Answer: D. Your friend was originally infected with bacteria that are resistant to at least two antibiotics. Question 4 Which of the following occurs after the creation of a new allele? Answer: A. The gene pool becomes more diverse. Question 5 A biologist has been studying two populations of trout in Montana for the last 25 years, when the two populations were established from one common population. In the southern population, the fish now have a slightly different mouth shape. But the northern population hasn’t changed from the original type. The new shape works well in catching the type of prey common in the habitat of the southern population. Which explanation is the most likely explanation of the gene differences in the two populations? Answer: B. The gene that produces the variation is probably still present in a small percentage of the northern population, but since there’s no advantage to having it, individuals with the variation aren’t preferentially selected. Question 6 A key prediction/implication of evolutionary theory is that: Answer: D. The frequency of alleles in a population changes over time in response to the environment Question 7 You notice that some squirrels in your neighborhood have a much darker coat color than most of the other squirrels. Is this darker color an adaptation? Answer: C. The trait is only an adaptation if it gives the squirrels an advantage in their habitat. Question 8 Which of the following traits can be acted on by natural selection? Answer: E. All of these can be acted on by natural selection, as long as they’re controlled by genes. Question 9 In 1980, only 1% to 5% of all Staphylococcus aureus isolates were MRSA strains. Now 60% to 70% of S. aureus isolates are MRSA strains. This is an example of: Answer: B. Directional selection of bacteria Question 10 As natural selection acts on a population, the amount of variation in the population should: Answer: A. Decrease Question 11 Which of the following is not a way in which the theory of evolution has been supported? Answer: E. None of the above. Question 12 Two unrelated individuals with the same color skin would: Answer: B. Be no more likely to have similar alleles for any gene that any two individuals chosen randomly Question 13 In a population where most of the individuals have long, narrow noses, a child is born with a shorter, broader nose. What’s the most likely explanation for this variation? Answer: B. The child reflects the normal variation around the average type. Question 14 Which individuals have the greatest fitness in an area where malaria is common? Answer: B. Individuals heterozygous for the normal and sickle cell anemia alleles Question 15 A small founder population of turtles has established a population on an island with a varied and good habitat. There is very little competition between members. What is the likely effect on evolution of this low level of competition? The population will remain very stable in size, and it won’t evolve much. Answer: B. The population will grow in size, and it won’t evolve much. Question 16 What is an allele? Answer: A. A particular version of a gene Question 17 Which of the following describes natural selection? Answer: B. A population of mammals varies in the length of their legs, water levels rise, and the habitat becomes swampy. The individuals with shorter legs are better able to swim to food, and the population evolves to become shorter legged. Question 18 Which of the following is true of individuals who are well adapted for a particular environment? Answer: D. They may or may not be equally fit in another environment. Question 19 In what way is artificial selection different from natural selection? Answer: D. In artificial selection, human preference is the selecting force; In natural selection, environmental conditions are the selecting force. Question 20 What is the evolutionary origin of light skin in humans? Answer: C. Light skin evolved several times in response to low ultraviolet light levels